Background: Surgical atrial ablation is evaluated by surgeons in relation to the estimated surgical risk. We analyze whether high-risk patients experience risk escalation by ablation procedures. Methods: The Case AF Registry is a prospective, multicenter, all-comers registry of atrial ablation in cardiac surgery. We analyzed the 1-year outcome regarding survival and rhythm endpoints of 1000 consecutive patients according to the operative risk classification (EuroscoreII ≤2 versus >2). Results: Higher NYHA score, ischemic heart failure, status post-stroke, renal insufficiency, COPD and diabetes mellitus were strongly represented in high-risk-patients (HRP). HRP exhibit more LVEF<40% (19.2 vs. 8.8%; p<0.001), but identical LA diameter and LVEDD compared to Low-risk-patients (LRP). CHA2DS-Vasc-score (2.4±1 vs. 3.6±1.5; p<0.001), sternotomies, combination surgeries, CABG, mitral valve procedures were increased in HRP. LRP underwent stand-Alone ablations as well. Ablation energy did not differ. LAA closure was performed in up to 86.1% (mainly cut-And-sew-procedures). Mortality corresponded to the original risk class without an escalation that may be related to ablation, stroke rate or myocardial infarction. 60.6% of HRP vs 75.1% of LRP were discharged in sinus-rhythm. Longterm EHRA-SCORE symptoms were lower in HRP. Repeated rhythm therapies were rare. Additional antiarrhythmics recieved a minority without group dependency. 1.6 vs. 4.1%(HRP) p=0.042, underwent long-Term-stroke, excess mortality was not observed. Anticoagulation remained common in HRP. Conclusion: Surgical risk and long-Term-mortality is determined by the underlying disease. In HRP freedom from atrial fibrillation and symptom relief can be achieved. Pre-operative risk scores should not lead to withholding an ablation procedure.